Cellulose derivative plastic composition



April 25, 1950 W. E. GLOOR CELLULOSE DERIVATIVE PLASTIC COMPOSITION Filed April 5, 1947' MIx cELLULosE DERIVATIVE, POLYMERIZABLE PLASTICIZER,

voLATILE soLvENT AND cATALYsTTo FORM PASTE MIx CELLULOSE DERIVATIVE, POLYMER|ZABLE PLAsTIcIzER, voLATILE soLvENT AND INHIBITOR TO FORM PASTE RoL PASTE 0N MILL To-coLLoID cELLULosE ROLL PAsTE ON MILL 'TO COLLOID cELLULosE' DERIVATIVE AND REMOVE SOLVENT DERIVATIVE No REMovE SOLVENT BREAK REsU LTANT sHEET UP INTO GRANULES OF MOLDING POWDER BREAK RESULTANT SHEET UP INTO GRANULES OF MOLDING POWDER R MovE RESIDUAL VOLATILE soLv NT REMOVE RESIDUAL VOLATILE soLvEN UNIFORMLY MIX THE RESULTING MOLDING POWDERS MOLD RESULTING MIXTURE TO DESIRED SHAPE WA LTE R E; GLOOR INVENTOR.

BY M

AGENT Patented Apr. 25, 1950 UNITED STATE canwnosr. DERIVATIVE PLASTIC COMPOSITION Walter E. Gloor, New Brunswick. N. J., assiznor to Hercules Powder Company, Wilmington, DeL, a corporation of Delaware Application April 5, 1947, Serial No. 739,642

This invention relatcs to compositions of ticizer of the type containing at least two nonconiugated double bonds.

Compounds having at least two nonconjugated double bonds, of whichdial lyl phthalate is exemplary, have been known to have a high solvent power for cellulose derivatives and the possibility of their use in the plastics art has been recognized. However, in this application they do not function as do the normal plasticizers for cellulose derivatives inasmuch as the compounds themselves are polymerizable under the infiuence of heat; and when used in conjunction with linear polymers such as the cellulose derivatives, they are believed to mechanically interlock the cellulosic polymer chains as well as to polymerize themselves. Thus, they are believed to effect what may be described as a vulcanization of the linear cellulosic polymers. Much support for this theory comes from the fact that the resulting plastics are nonthermoplastic or tend in that direction. Although it hasbeen customary in the use of these compounds to employ a catalyst such as benzoyl peroxide, the polymerization and cross-linking proceeds without a catalyst only at a slower rate. The plastic products, in addition to tending towards being nonthermoplastic, are quite hazy, hard, brittle, and have poor weather resistance.

Now, in the accordance with this invention, it has been found that the above objections to the use of polymerizing plasticizers in cellulose derivative base plastics may be obviated by separately compounding two different molding powders, one based on the use of an organic peroxide catalyst and the other based on the use of a polymerization inhibitor, mixing these two powders, and finally molding the admixed powder in'a desired shape. At least 20% inhibitor-bearing molding powder should be employed in the mixture to provide a plastic having the required thermoplasticity.

In the preparation of the inhibitor-containing or inhibited molding. powder, the polymerizable plasticizer, cellulose derivative and, as an inhibitor, a small amount of an aromatic compound having atleast one OH group or at least one amine group attached directly to the aromatic nucleus are admixed to efiect colloidization of the .cellulose derivative. Any of the procedures known to the art may be employed,

as high pressure mixing in a Banbury mixer.

14 Claims. (Cl. 260-17) mixing the ingredients with a volatile solvent ,to form a paste which can be milled on a, roll mill, etc. The colloided mass ultimately obtained is broken up into granules of molding powder. In the preparation of catalyst-containing or catalyzed molding powder, similar ingredients are compounded with the exception that an organic peroxide catalyst is used to replace the inhibiting compound.

Having now indicated in a general way the nature and purpose of the invention, reference is made to the accompanying drawing which illustrates one embodiment of the invention wherein the compounding of the two types of molding powders is carried out by the solvent process, the molding powder preparation being followed by the steps of intimately and uniformly admixing the two molding powders and subjecting the resulting admixture to molding condi- In order to illustrate how the principles of the invention may be employed, the following specific examples are given.

Molding powders were made up on the basis of the following formulations by the solvent process. The ingredients shown in Table I were mixed with about 50 parts of ethyl alcohol and about 50 parts of acetone at room temperature where the formula included cellulose acetate of 53.0% acetic acid content, and with parts of acetone where the formula included cellulose acetate of 57.0% acetic acid content. The mixing was carried out in a Baker-Perkins mixer, with F. water running through the jacket, for a period of about 95 minutes. The resulting pastes were then rolled on a two-roll mill, with F. water running through the core, to about 15% solvent content. Upon cooling to room temperature, the resultant sheets were broken up in a rotary cutter to molding powder having a particle size of A; in. to in. These granules were heated at 180 F. for 24 hours in a tray drier.

Table I Conventional catalyzed Formulation Cellulose Aceta e (53.0%

combined acetic acid).-.. Cellulose Acetate (57% combined acetic acid).---. Diallyl phthalare Diethylnhthalate Benzoylperoxide. Hydroquinone Blends were made by blending the powders of Examples 3 and 5, using 50% by weight of each.

' higher than the "flow temperature" of the plastic composition, into a A in. x 55 in. x in. bar mold. Discs for "hardness and water absorption" were molded in a positive-type compression mold, using a molding temperature of 320 F. and 1500 lb./sq. in.- pressure, and charging enough molding powder to give a disc V in. or in. thick 2 as called for by A. S. T. M. specifications. The results of the tests are shown in the following Table II.

Table H 4 be trulythermopiastic. 'lheyalsohavegoodoutdoor weatherability as evidenced by the fact that they have not shown failures of any typ after gitzsyide exposure for 8 to 11 months at Parlin, Additional molding powders were prep red using the following formulations in the same manher as employed for Examples 1 to 6, inclusive.

Table III Cellulose Acetate (53.0% combined acetic acid) 06 60 --.i06 M i 'edace a 70 72 Diallyl phtfaia 34 31 Z Benzoyl pnaxidem- 0.3 0.3 0.3 0 3 0 Hydroquinone 2 Blends of the powders of Examples 7 and 11, 8 and 12, 9 and 13, and 10 and 14 were prepared Properties 1 2 3 4 a 2:

Flow 'lem aim. c. is! no 141 mu m m Rockwell M" Hardness; 15 31 97 81 20 64 Water Absorption 24 hrs., percent L2 3. l2 2. 01 1.81 2. 56 2.88 1. 70 Percent Plasticizer I088 l. 05 0. 31 r 0. 0i 0. 13 0. 46 0. 0 glgfarpy Iflmpactait.-m.:g&tfil)i in t 2. 8 0. 7 0. 3 0. 3 1. 5 0. 9

orma onun er .sq. peroen hour 41. a as. e a1 a4 29.5 21.5

Dimensional Stability Test: I

Percent maximum diameter change 0. 5 7. 5 0. 5 0.4 1. 0 -o 8 lz zss eea E2 35% ii? iii 11'; 15:3

rcen mum we c cmf; Clear Clear Opaque Opaque Bligtbtiy Slightly mo mo at 20 F.; 24 hrs. at 170 F.; 24 hraat -2o F; 24 hrs. at 170 F. and 65% R. H.

Consideration of the above data indicates-that, as compared with the corresponding convenby tumbling equal parts thereof by weight for about 10 minutes to obtain uniform mixtures.

tional plastics, the blended plastics have greater These blended powders, also the unblended cataheat resistance as shown by the higher flow temperatures. Furthermore, they show distinct improvement over the corresponding conventional plastics both with respect to moisture resistance and retention of plasticizer.

lyzed powders were tested comparatively by molding the powders into various test shapes as explained hereinabove. These shapes were tested in accordance with standard procedures. The re- The blended plassults follow:

Table IV Blend Blend Blend Blend Properties 11 12 13 I 14 741 842 943 NH Flow Tem ature. 0- 153 161 160 165 143 141 ggckwell mM" fiaggnfgsun 51 00 50 34 16 27 4 5 t N c l finff. E? 1.0 0.8 0.3 0.9 4.1 1.8 0.8 1.4 Color Opaque Opaque Opaque Opaque Slightly Slightly Clear Clear mottled mottled Water Absorption 24 h18.,

percent 2.41 2-58 2.24 2.40 2.04 2.51 2.58 2.20

ties are also-improved in resistance to deformation and "in dimensional stability, as shown by the dimensional stability test.

While the blended plastics are not quite as tough as the conventional plastics as shown by their impact, values, they show considerable improvement over the catalyzed plastics in this respect and possess sufllcient toughness to be of utility in many diverse commercial applications. The lower hardness values of the blended plastics as compared with the catalyzed is consistent with the data on impact strength. The blended plastics in view of all the data may be said to 7;,

as spending catalyzed samples.

represent serious drawbacks to their utility. By

the use of blended powders these defects have been overcome. At the same time it will be noted 7 that the blended plastics approach the catalyzed samples with respect to water resistance.

Cellulose derivatives-other than cellulose acetate may be employed in carrying out the invention. Thus, for example, cellulose inorganic acid esters, as cellulose nitrate, etc.; cellulose organic hydroquinone, p-phenyl phenol,

accepts esters, as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate stearate, cellulose acetate caproate, etc.; and cellulose ethers, as ethyl cellulose, benzyl' cellulose, etc., may be employed. The particular derivative employed will be one having a. degree of esteriflcation or etheriiication, as the case may be, within. the ranges'normally used for the preparation of plastic products. Thus, cellulose acetate, to which this invention has particular application, will, if employed, have an acetic acid content between about 51.0% and 59.0%, preferably between about 5'l.0% and 58.0%. It is furthermore preferred that the cellulose acetate employed have a chain length corresponding to an intrinsic viscosity of 1.0 or higher, as determined by the method of Kraemer, see Journal of Industrial 8: Engineering Chemistry, 30, 1200 (1938). All of the cellulose derivatives set forth above are thermoplastic.

The examples have shown the use of diallyl phthalate as a polymerizable plasticizer. However, this compound is merely representative of a class of compounds which may beused for the 5 2 I in any particular case may besuch as t'o-be solsame, purpose. Thus, any organic ester characterized by having at least one ester linkage, said ester containing the polymerizable group taining an oleflnic double bond separated therefrom by at least one intervening ester linkage so that the double bands do not form a conjugated system, maybe employed. For example,-

vinyl or allyl esters of polybasic acids, such as succinic, adipic, phthalic, citric, tartaric, sebacic, etc.; acrylic and alpha-substituted acrylic esters of polyhydric alcohols, such as glycol, glycerol, diethylene glycol, trimethylene' glycol, etc.; vinyl or allylesters of. acrylic or crotonic acids, etc., may be employed. Of these various compounds, the allyl esters of polybasicforganic'acids are preferred, particularly the esters of phthalic, adipic'fand citric acids. If desired, any of the conventionally employed plasticizers for the particular cellulose derivative being used may be employed in conjunction with the above polymerizable plasticizers in preparing the molding powders to beblended in accordance with the invention, provided they are sufficiently compatible with the other ingredients. In order to achieve the benefits of the use of the polymerizable-type plasticizer, however, the total plastihydroxyl group or at least one amine group attached directly to the aromatic nucleus may be employed. Thus, for example, phenols, as phenol,

eatechol, p-

1. e., mixed with the cellulosetderivativefpolyly dispersed throughout the plastic mass. It, is, I furthermore, preferred that the: agent be intro 0 thyl-p-phenylene diamine. etc.; amino-substituted phenols, as p-amino phenol, tyrosine ethyl ester, etc.; may be employed. Of these various compounds, aromatic compounds having not.

more than 13 carbon atoms have given the best results, with hydroquinone being preferred.

In regard to the amount of suchagent to employ in any particular case,' it is obvious that varying amounts can be employed to achieve difi'erent efiects. Thus. it may not be desired to stop the polymerizing or vulcanizing action of the plasticizer entirely in which event a comparatively small amount of the agent will be employed. In general, between about 0.01% and 'about 5.0%

nonvolatile ingredients of the inhibited molding powder. Of the broad general class of agents which have been found effective in-impeding the polymerizing and vulcanizing reactions of ,the'" polymerizable plasticizers employed in the com positions'oi this invention, the agent employed uble in the plastic mass, orit may be present in the plastic mass in flnely-divided form uniform-L duced prior to commencement of-the colloiding "of the particular cellulose derivative-employed,

" merizable plasticizer, etc., before the mass is a; mixer of the Banbury type. etc.

milled on a hot roll mill, mixed in a high pressure In preparingthe' molding powders containing a catalyst for the polymerizing plasticizer, the

ingredients and proportions thereof are much the same as those employed in preparing the inhibited powders, the only exception being the replacement of the inhibitor by a catalyst. The catalysts which have proven most effective and productive of uniformity of results, at this point in the process, are the organic peroxides. Speciilcally, of the class of organic peroxide catalysts, benzoyl. peroxide, t-butyl peroxide, lauryl peroxide, acetobenzoyl peroxide, acetyl peroxide, bis(p-chlorobenzoyl) peroxide, bischloroacetyl peroxide, bistriphenylmethyl peroxide, ethyl n.- hydroxybenzyl peroxide, and bismethoxymethyl peroxide have proven effective. Benzoyl peroxide is preferred.

In general, the organic peroxide catalyst is employed in the preparation of catalyzed molding powders in somewhat smaller amounts than is the inhibitor in the preparation of inhibitor-containing powders. Between about 0.01% and about 2.0% peroxide catalyst based on the nonvolatile ingredients of the catalyzed molding powder may be employed, between about 0.10% and about 0.65% being preferred. I

In carrying out the preceding examples, the

, colloiding of the cellulose derivative was effected menthyl phenol, p-hydroxy phenyl stearate, hy-

droquinone monobenzyl ether, benzyl catechol. etc.; primary amines, as alpha-naphthylamine, phenyl beta-naphthylamine, etc.; secondary amines, as diphenyl amine, diphenyl hydrazine, diphenyl guanidine. symmetrical dibeta-naphby the "solvent process in which a volatile solvent for the cellulose derivative and plasticizer was mixed therewith to form a paste and the paste then milled on a hot roll mill to remove most of the volatile solvent and form a homoeneous colloided mass of the cellulose derivative and plasticizer. The invention with which this application is concerned, however, is not limited to carrying out the colloiding and subsequent operations of shaping, granulation to form molding powder, etc., in any particular manner. Any of the processes known to the art particularly aromas may be employed. Thus, colioiding may be effected by high pressure mixing (without the use of volatile solvent) as in a Banbury mixer, by

the use of an aqueous slurry of the cellulose derivative to which the plasticizer is added with derivative to polymerizable plasticizer employed may be varied considerably depending on the mechanical properties desired in the finished plastics. Furthermore, ingredients in addition to the essential ones may be employed, as for example,

. resins, gums, fillers,v dyes, pigments, etc. The

methods of incorporation of these ingredients and the adiu'stment of formulations to achieve desired properties of the finished products are known to the art.

Both the catalyzed and inhibited powders prepared for use in accordance with the method of the invention should have an average particle size below about in., an average particle size between about 1 in. and about in. being most eilectivein producing finished blended plast'cs of optimum structural characteristics. It will be apparent, too, that the more uniform the particle size, the more uniform structural characteristics are obtainable in the finished plastics.

In blending the two types of molding powders, from about 20% to about 90% of the total weight of the blend should be inhibitor-containing molding powder. Furthermore, it is preferred to'eme ploy between about 40% and about 60% of inhibitor-containing powder in order to obtain plastics suillciently tough to have a rather wide range of commercial application. The remainder of the blend is normally catalyzed molding powder. However, if desired, up to 90% of such remainder may be a moldin powder, based on regular or nonpolymerizing-type plasticizer. The actual blending may be carried out in any suitable device as, for example, a tumbling barrel. The blending operation should be of sufficient duration to assure a uniform mixture.

The impact-enhancing effect of the blended plastics prepared in accordance with this invention appears to be due to the fact that polymerization takes place in the center of the catalyzed granules, polymerization becoming less as the inhibitor in the inhibited granules penetrates into them. The resulting plastic has a slightly mottled appearance, the clearer spots being left by the inhibited granules and the more opaque areas being left by the catalyzed granules. This gives a more or less laminated structure having interspersed zones of polymerized plasticizercellulose derivative and inhibited plasticizercellulose derivative whereby hardness variations are obtained in an otherwise homogeneous struc ture. These local differences in hardness from one granule to another have the eflect of neutralizing or breaking up molded-in strains in a molded piece so that they cannot distort the material upon exposure to water vapor.

As compared with conventional plastic formulations, i. e., those containing unpolymerizable plasticizers, the plastics prepared in accordance with this invention are more heat-resistant and show substantial improvement both'in respect to resistance to moisture and retentivity of plasticizer. These new plastics are more deformationresistant and more dimensionally stabl than the present day plastics having a cellulose derivative base, yet they are very nearl as tough as indicated by their high impact strength. The

cold flow-tendencies of these new plastics are re-v duced below those exhibited by the conventional plastics. Pigmented types mold smoothly, have good mold reproduction and appear uniform in structure. These individual characteristics combine to provid excellent outdoor weathering properties.

As compared with plastics formulated on the basis of a polymerizable plasticizer including a polymerization catalyst, the subject plastics are considerably tougher, and while the do not possess the equivalent dimensional stability, they do show an improvement over conventional plastics in this respect.

It will be understood that all parts and percentages herein are by weight unless otherwise mentioned.

. What I claim and desire to protect by Letters Patent is:

1. A thermoplastic composition comprising a mixture of granules of a catalyzed molding material and of an inhibited molding material, the granules of both materials having an average granule size less than about inch, said inhibited material comprising from about 20% to about %.0! the weight of the thermoplastic composition, the catalyzed material and the inhibited material each comprising a thermoplastic cellulose derivative of the group consisting of cellulose esters and cellulose ethers and a, plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of a compound compatible with said cellulose derivative and capable of polymerization per se to a nonthermoplastic material, said compound being an organic ester having at least one ester linkage, said ester containing the polymerizable group C=CH2 and at least one other polymerizable group containing an olefinic double bond separated therefrom by at least one intervening ester linkage so that the double bonds do not form a conjugated system, said catalyzed material essentially containing about 0.01% to about 2% of an organic peroxide catalyst based on .the nonvolatile ingredients in said catalyzed material, said inhibited material essentially containing about 0.01% to about 5% of an inhibitor of the group of phenols, aromatic primary amines, aromatic secondary amines, and amino-substituted phenols based on the nonvolatile ingredients in said inhibited material.

2. A thermoplastic composition comprising a mixture of granules of a cata yzed molding material and of an inhibited molding material, the granules of both materials having an average granule size less than about inch, said inhibited material comprising from about 20% to about 90 of the weight of the thermoplastic composition, the catalyzed material and the inhibited material each comprising a thermoplastic cellulose derivative of the group consisting of cellulose esters and cellulose ethers and a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of an aliyl ester of an organic polycarboxylic acid compatible with said cellulose derivative, said catalyzed material essentially containing about 0.01% to about 2% of an organic peroxide catalyst based on the nonvolatile ingredients in said catalyzed material, said inhibited material essentially containing about 0.01% to about 5% of an inhibitor of the group of phenols, aromatic primary amines, aromatic secondary amines, and amino-substituted phenols based on granules'of both. materialshaving an average mixture ot'granulesof a catalyzed molding material andof aninhibited'molding material, the

granule size-less than aboutlfl inch, said inhibited material comprising-from about 20% to about 90% oftlie weight of the thermoplastic composition, the catalyzed'material andthe inhibited material each comprising a thermoplastic cellulose acetate 'and 'a. plasticizer therefor, said plasticizer in eaoh'oi said catalyzed material and saidJnhibited material-comprising at least 50% by W18ht Of a-c'ompound compatible with said cellulose. acetate; 'and capable oi polymerization per se to a nonthermoplastic material, said compound'being an organic ester; having atleast one ester; linkage, said: ester containing the polymerizablegroup ,C-TCH2 and at least one other polymerizable group containing an volefinic double bond separated'tlierefrom by at least one intervening ester'linkag'e so that thedouble bonds do not ior'mja conjugated system, said catalyzed material essentially containing about 0.01% to about 2% of anorganic peroxide catalyst-based'on the nonvolatile ingredients in-=said ,cata-Zyzeclmaterial, said inhibitedmaterial essentially containingabout 0.01% to1about5% -'of, 'an inhibitor of theg'roup of.phenols; aromatic p ry amines, aromaticsecondary .'amines,' and amino-substitutedphenols based'on the nonvolatile ingredients in said inhibited material.

' 4. A thermoplastic composition comprising a mixture of granules of a catalyzed molding material and of an inhibited molding mate; la], the granules of bothmaterials having an average granule size less than about inch, said inhibited material comprising from about 20% to about 90% of the weight of the thermoplastic composition, the catalyzed material and the inhibited material each comprising a thermoplastic cellulose derivative of the group consisting of cellulose esters and cellulose ethers and a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of diallyl phthalate, said catalyzed material essentially containing about 0.01% to about 2% of an organic peroxide catalyst based on the nonvolatil ingredients in said catalyzed material, said inhibited material essentially containing about 0.01% to about 5% of an inhibitor of the group of phenols,

aromatic primary amines, aromatic secondary amines, andamino-substituted phenols based on the nonvolatile ingredients in said inhibited material.

5. A thermoplastic composition comprising a mixture of granules of a catalyzed molding material and of an inhibited molding material, the granules of both materials having an average granule size less than about it; inch, said inhibited material comprising from about 20% to material essentially containing about 0.01% to about 5% of an inhibitor of the group of phenols,

aromatic primary amines, aromatic secondary amines, and amino-substituted phenols based on ttleie1 nonvolatile ingredients in said inhibited ma- 6. n thermoplastic composition comprising a mixtureoi granules of a catalyzed molding ma terial and of an inhibited molding material, the granules of both materials having an average granule size less than about inch, said inhibited material comprising from about 20% to about 90% of the weight of the thermoplastic composition, the catalyzed material and the inhibited material each comprising a thermoplastic cellulose derivative of the group consisting of cellulose esters and cellulose ethers and a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of diallyl adipate, said catalyzed material essentially containing about 0.01% to about 2% of an organic peroxide catalyst based on the nonvolatile ingredients in said catalyzed material, said inhibited material essentially containing about 0.01% to about 5% of an inhibitor of the group of phenols, aromatic primary amines, aromatic secondary amines, and amino-substituted phenols based on the nonvolatile ingredients in said inhibited material. I 7. A- thermoplastic composition comprising a mixture of granules of 2. catalyzed molding material and of an inhibited molding material, the granules of both materials having an average granule size less than about inch, said inhibited material comprising from about 20% to about of the weight of the thermoplastic composition, the catalyzed material and the inhibited material each comprising a thermoplastic cellulose acetate and a'plasticizer thereior, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of diallyl phthalate, said catalyzed material essentially containing about 0.01% to about 2% of benzoyl peroxide based on the nonvolatile ingredients in said'catalyzed material, said inhibited material essentially containing about 0.01% to about 5% of hydroquinone based on the nonvolatile ingredients in said inhibited material.

8. A thermoplastic composition comprising a mixture of granules of a catalyzed molding material and of an inhibited molding material, the granules of both materials having an average granule size less than about inch, said inhibited material comprising from about 20% to about 90% of the weight of the thermoplastic composition, the catalyzed material and the inhibited material each comprising a thermoplastic cellulose acetate and a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of triallyl citrate, said catalyzed material essentially containing about 0.01% to about 2% of benzoyl peroxide based on the nonvolatile ingredients in said catalyzed material, said inhibited material essentially containing about 0.01% to about 5% of hydroquinone based on the nonvolatile ingredients in said inhibited material.

9. A thermoplastic composition comprising a mixture of granules of a catalyzed molding material and of an inhibited molding material, the granules ofboth materials .having an average granule size less than about inch, said inhibited material comprising from about 20% to about 90% of the weight of the thermoplastic compo- 1 sltion, the catalyzed material and the inhibited material each'comprising a thermoplastic cellulose aceate and a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at'least 50% by weight of diallyl adipate, said catalyzed material essentially containing about 0.01% to about 2% of benzoyl peroxide based on the nonvolatile ingredients in said catalyzed material, said inhibited material essentially containing about 0.01% to about 5% of hydroquinone based on the nonvolatile ingredients in said inhibited material.

10. A thermoplastic composition comprising a molded mass of a mixture of granules of a catalyzed molding material and of an inhibited molding material, the granules of both materials having an average granule size less than about inch, said inhibited material comprising from about 20% to about 90% of the weight of the thermoplastic composition, the catalyzed mate rial and the inhibited material each comprising a thermoplastic cellulose derivative of the group consisting of cellulose esters and cellulose ethers and a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of a compound compatible with said cellulose derivative and capable of polymerization per se to a nonthermoplastic material, said compound being an organic ester having at least one ester linkage. said ester containing the polymerizable group C= CH2 and at least one other polymerizable group containing an olefinic double bond separated therefrom by at least one intervening ester linkage so that the double bonds do not form a conjugated system, said catalyzed material essentially containing about 0.01% to about 2% of an organic peroxide catalyst based on the nonvolatile ingredients in said catalyzed material, said inhibited material essentially containing about 0.01% to about 5% of an inhibitor of the group of phenols, aromatic primary amines, aromatic secondary amines, and amino-substituted phenols 90% by weight of the first molding powder with about 80 %"to about by weight of the second molding powder and subjecting the resulting mixture to molding conditions.

12. The process of making a thermoplasti cellulose derivative plastic which comprises preparing a first molding powder by admixing a thermoplastic cellulose derivative of the group consisting-of cellulose esters and cellulose ethers, a plasticizer therefor, said plasticizer in each of said catafyzed material and said inhibited material comprising at least 50% by weight of an allyl ester of an organic polycarboxylic acid compatible with said cellulose derivative, and about 0.01% to about 5% of an inhibitor of the group of phenols, aromatic primary amines, aromatic secondary amines, and amino-substituted phenols based on the nonvolatile ingredients in said molding powder; colloiding the admixture to form a colloided mass; breaking up the resulting colloided mass into granules ofmolding powder having an average granule size below about 1; inch; preparing a second molding powder using the same ingredients with the exception that about 0.01% to about 2% of an organic peroxide catalyst is substituted for the aforesaid inhibitor;

admixing about 20% to about 90% by weight of the first molding powder with about 80% to about 10% by weight of the second molding powder and giiigjecting the resulting mixture to molding conons.

13. The process of making a thermoplastic cellulose derivative plastic which comprises preparing a first molding powder by admixing a thermoplastic cellulose aceate, a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least by weight of a compound compatible with said cellulose acetate and capable of polymerization per se to a nonthermoplastic material, said compound being an organic ester having at I least one ester linkage, said ester containing the based on the nonvolatile ingredients in said inhibited material.

11. The process of making a thermoplastic cellulose derivative plastic which comprises preparing a first molding powder by admixing a thermoplastic cellulose derivative of the group 1 consisting of cellulose esters and cellulose ethers,

a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of a compound compatible with said cellulose derivative and capable of polymerization per se to a nonthermoplastic material, said compound being an organic ester having at least one ester linkage; said ester containing the polymerizable group C=CH2 and at least one other polymerizable group containing an olefinic double bond separated therefrom by at least one intervening ester linkage so that the double bonds do not form a conjugated system, and about 0.01% to about 5% of an inhibitor of the group of phenols, aromatic primary amines, aromatic secondary amines, and amino-substituted phenols based on the nonvolatile ingredients in said molding powder; colloiding the admixture to form a colloided mass; breaking up the resulting colloided mass into granules of molding powder having an average granule size below about inch; preparing a second molding powder using the same ingredients with the exception that about 0.01% to about 2% of an organic peroxide catalyst is subsituted for the aforesaid inhibitor; admixing about 20% to about po'ymerizable group C=CH2 andv at least one other polymerizable group containing an oleflnic double bond separated therefrom by at least one intervening ester linkage so that the double bonds do not form a conjugated system, and about 0.01% to about 5% of an inhibitor of the group of phenols, aromatic primary amines, aromatic secondary amines, and amino-substituted phenols based on the nonvolatile ingredients in said molding powder; colloiding the admixture to form a colloided mass; breaking up the resulting colloided mass into granules of molding powder having an average granule size below about 1"; inch; preparing a second molding powder using the same ingredients with the exception that about 0.01% to about 2% of an organic peroxide catalyst is substituted for the aforesaid inhibitor; admixing about 20% to about 90% 'by weight of the first molding powder with about to about 10% by weight of the second molding powder and subjecting the resulting mixture to molding conditions.

14. The process of making a thermoplastic cellulose derivative plastic which comprises prepaL'ing a first molding powder by admixing a thermoplastic cellulose acetate, a plasticizer therefor, said plasticizer in each of said catalyzed material and said inhibited material comprising at least 50% by weight of an allyl ester of an organic polycarboxylic acid and compatible with said cellulose acetate, about 0.01% to about 5% of hydroquincne on the basis of the total nonvolatile ingredients of the admixture; colloiding the adthe first molding powder with about 80% to about 10% by weight of the second molding powder and subjecting the resulting mixture to molding conditions.

WALTER E. GLOOR.

REFERENCES CITED The following references are of record in the file of this patent:

gnome:

14 mu'rnn s'ra'ras PATENTS Number Number Name Date Renfrew Jan. 11, 1938 Garvey Apr. 25, 1939 Freund Dec. 14, 1943 Dean Apr. 17, 1945 Muskat June 26, 1945 Pechukas et a] May 20, 1947 Kropa June 22, 1948 FOREIGN PATENTS Country Date Great Britain Oct. 8, 1941 Great Britain Oct. 8, 1941 

1. A THERMOPLASTIC COMPOSITION COMPRISING A MIXTURE OF GRANULES OF A CATALYZED MOLDING MATERIAL AND OF AN INHIBITED MOLDING MATERIAL, THE GRANULES OF BOTH MATERIALS HAVING AN AVERAGE GRANULE SIZE LESS ABOUT 3/16 INCH, SAID INHIBITED MATERIAL COMPRISING FROM ABOUT 20% TO ABOUT 90% OF THE WEIGHT OF THE THERMOPLASTIC COMPOSITION, THE CATALYZED MATERIAL AND THE INHIBITED MATERIAL EACH COMPRISING A THERMOPLASTIC CELLULOSE DERIVATIVE OF THE GROUP CONSISTING OF CELLULOSE ESTERS AND CELLULOSE ETHERS AND A PLASTICIZER THEREFOR, SAID PLASTICIZER IN EACH OF SAID CATALYZED MATERIAL AND SAID INHIBITED MATERIAL COMPRISING AT LEAST 50% BY WEIGHT OF A COMPOUND COMPATIBLE WITH SAID CELLULOSE DERIVATIVE AND CAPABLE OF POLYMERIZATION PER SE TO A NONTHERMOPLASTIC MATERIAL, SAID COMPOUND BEING AN ORGANIC ESTER HAVING AT LEAST ONE ESTER LINKAGE, SAID ESTER CONTAINING THE POLYMERIZABLE GROUP >C=CH2 AND AT LEAST ONE OTHER POLYMERIZABLE GROUP CONTAINING AN OLEFINIC DOUBLE BOND SEPARATED THEREFROM BY AT LEAST ONE INTERVENING ESTER LINKAGE SO THAT THE DOUBLE BONDS DO NOT FORM A CONJUGATED SYSTEM, SAID CATALYZED MATERIAL ESSENTIALLY CONTAINING ABOUT 0.01% TO ABOUT 2% OF AN ORGANIC PEROXIDE CATALYST BASED ON THE NONVOLATILE INGREDIENTS IN SAID CATALYZED MATERIAL, SAID INHIBITED MATERIAL ESSENTIALLY CONTAINING ABOUT 0.01% TO ABOUT 5% OF AN INHIBITOR OF THE GROUP OF PHENOLS, AROMATIC PRIMARY AMINES, AROMATIC SECONDARY AMINES, AND AMINO-SUBSTITUTED PHENOLS BASED ON THE NONVOLATILE INGREDIENTS IN SAID INHIBITED MATERIAL. 